Network Working Group                                        J. Pezeshki
Internet-Draft                                                E. Ertekin
Intended status: Experimental
Expires: February 16, 2009                                     R. Jasani
Expires: July 3, 2008
                                                             C. Christou
                                                     Booz Allen Hamilton
                                                       December 31, 2007
                                                         August 15, 2008

    IKEv2 Extensions to Support Robust Header Compression over IPsec

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This Internet-Draft will expire on July 3, 2008.

Copyright Notice

   Copyright (C) The IETF Trust (2007). February 16, 2009.


   When using Robust Header Compression (RoHC [ROHC]) in conjunction

   In order to integrate RoHC with IPsec [IPSEC] (i.e.  [RoHCOIPSEC]) [ROHCOIPSEC], a mechanism is
   needed to negotiate RoHC configuration parameters between end-points prior to
   operation. end-points.
   Internet Key Exchange (IKE) is a mechanism which can be leveraged to
   handle these negotiations.  This document specifies extensions to Internet Key Exchange (IKEv2 [IKEV2])
   IKEv2 [IKEV2] that will allow RoHC and its associated configuration
   parameters to be negotiated for IPsec security associations (SAs).

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  RoHC Channel Negotiation  . . . . . . . . . . . . . . . . . . . 3
     2.1.  Negotiation of RoHC Channel Parameters  . . . . . . . . . . 3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8
   Intellectual Property and Copyright Statements  . . . . . . . . . . 9

1.  Introduction

   Increased packet header overhead due to IPsec protection [IPSEC] can result in
   the inefficient utilization of bandwidth.  Coupling RoHC [ROHC] with
   IPsec offers an efficient way to transfer protected IP traffic.

   For proper

   The operation of RoHCoIPsec [ROHCOIPSEC] operation, RoHC requires configuration
   parameters to be negotiated between the compressor and
   decompressor, prior to operation. decompressor.
   Current specifications of hop-by-
   hop for hop-by-hop RoHC schemes negotiate these parameters
   through a link-layer protocol such as Point-to-Point Protocol (PPP)
   (i.e.  RoHC over PPP [ROHCPPP]).  Similarly,  Since key exchange protocols (e.g.
   IKEv2) are
   commonly can be used to negotiate parameters between IPsec peers before a SA
   can be established.  This peers, this
   document proposes the use of IKEv2 to
   handle RoHC channel configuration for RoHCoIPsec, and details various defines extensions to IKEv2 which are intended to provide this functionality. negotiate RoHC parameters for

2.  RoHC Channel Negotiation

   The initialization of a RoHC session requires the negotiation of a
   set of configuration parameters (e.g.  MAX_CID, etc.).  As such, a
   mechanism must exist for a RoHC enabled device  The following
   subsections define extensions to share IKEv2 which enables an initiator to
   propose a list set of
   supported RoHC parameters with its peer, and for parameters; the peer to select responder selects the
   appropriate parameters from this list.

   Similarly, negotiable parameters must also be shared between IPsec
   peers before a SA can be established.  To perform this negotiation, a
   key exchange protocol, IKEv2, is commonly used.  IKEv2 is an
   extensible protocol that negotiates parameters via request/response
   message pairs (i.e. exchanges).

   A set of extensions to IKEv2 can be defined, which will allow for
   RoHC parameters to be negotiated during the creation list, and rekeying of
   Child SAs.  This new Notify payload will contain values for responds with the set
   of RoHC accepted
   parameters to be negotiated between for the two RoHC peers. channel.

2.1.  Negotiation of RoHC Channel Parameters

   RoHC configuration parameters will be negotiated at either the
   establishment or rekeying of a Child SA.  Specifically, a new Notify
   payload will be is used during the IKE_AUTH and CREATE_CHILD_SA exchanges to
   negotiate the RoHCoIPsec session. these parameters.

   The Notify payload sent by the initiator will contain contains the configuration
   parameters for the RoHC scheme. implementation.  Upon receipt of the
   initiator's request, the responder will either ignore the payload (if
   it doesn't support RoHC or the proposed parameters) or respond with a
   Notify payload that contains the accepted RoHC channel parameters.  These
   The accepted parameters are subset of an intersection between the parameters
   proposed by the initiator, initiator and the parameters supported by the
   responder (e.g. if the initiator proposes a MAX_CID value of 15, but
   the responder only supports a MAX_CID value of 13, the responder will
   respond with a value of 13, which is supported by both parties).

   Note that only one Notify payload is used to convey RoHC parameters
   per exchange.  If multiple Notify payloads relaying RoHC parameters
   are received by the responder, all but the first such Notify payload
   must be dropped.  If the initiator does not receive a Notify Payload
   with the responder's accepted RoHC channel parameters, RoHC must not
   be enabled on the Child SA.

   A new Notify Message Type value, denoted ROHC_SUPPORTED, will be
   added to indicate that the Notify payload is conveying RoHC channel
   parameters.  Additionally, several fields of the Notify payload (as
   defined in [IKEV2]) are set as follows:

   Critical (1 bit)
      This value is set to zero to indicate that the recipient must skip
      this payload if it does not understand the payload type code in
      the Next Payload field of the previous payload.

   RESERVED (7 bits)
      Must be sent as zero, and must be ignored on receipt.

   Protocol ID (1 octet)
      If the RoHC parameters are set at SA creation, and thus do not
      relate this field must be
      set to zero.  If this notification concerns an existing SA, this field must
      value may be set to zero. (2) AH [AH], or (3) ESP [ESP].

   SPI Size (1 octet)
      This value must be set to zero, since no SPI is applicable (RoHC
      parameters are set at SA creation, thus the SPI has not been

   Notify Message Type (2 octets)
      This field must be set to ROHC_SUPPORTED.

   RoHC configuration parameters will be communicated via a new Notify
   message type, denoted ROHC_SUPPORTED.  The RoHC configuration
   parameters will be listed within the Notification Data field of the
   Notify payload, payload in the following format: format (default values for the
   configuration parameters are consistent with [ROHCPPP]):

                           1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      !            MAX_CID            !              MRRU             !
      !           MAX_HEADER          !         PROFILE LENGTH        !
      !                                                               !
      ~                           PROFILES...                         ~
      !                                                               !
      !                                                               !
      ~                     INTEGRITY ALGORITHMS...                   ~
      !                                                               !

     Figure 1: 1.  Notification Data field for the ROHC_SUPPORTED Notify
                               message type.

   MAX_CID (2 octets)
      The MAX_CID field indicates the maximum value of a context
      identifier.  This value must be at least 0 and at most 16383 (The
      value 0 implies having one context).

      Suggested value: 15

      Note: The value of LARGE_CIDS will be implicitly determined by
      this value (i.e. if MAX_CID is <= 15, LARGE_CIDS will be assumed
      to be 0).

   MRRU (2 octets)
      The MRRU field indicates the maximum reconstructed reception unit
      (see [ROHC], section 5.1.1).

      Suggested value: 0

      The MRRU value is used in conjunction with the segmentation
      protocol defined in RoHC.  Since RoHCoIPsec will generally be RoHC is implemented across multiple link-layer "hops", over an IPsec
      SA, RoHC segmentation will is not normally be required.  In these cases possible.  Therefore, the MRRU value will
      must be set to zero, indicating that no segment headers are
      allowed on the channel.

   MAX_HEADER (2 octets)
      The largest header size in octets that may be compressed.

      Suggested value: 168 octets
      Note: The MAX_HEADER parameter is not used for all RoHC profiles.
      If none of the RoHC profiles require this field, this value is

   PROFILE LENGTH (2 octets)
      The total number of profiles contained within the PROFILES field
      (note that each RoHC profile is 2-octets in length).

      The set of profiles to be enabled for the RoHC process.  Profiles
      are further detailed in [ROHC].  In addition, several common
      profiles are defined in [ROHCPROF].  These 16-bit profile
      identifiers are to be sent in network byte order.

      The set of Integrity Algorithms that may be use to ensure the
      integrity of the decompressed packets (i.e. ensure that the
      packets packet
      headers are properly decompressed).  Each Integrity Algorithm is
      represented by a 2-octet value that corresponds to the value
      listed in [IKEV2-PARA] "For Transform Type 3 (Integrity
      Algorithm)" section.

      It is noted that:
      1.  The length of this field is inferred from the Notify Payload's
          "Payload Length" field ([IKEV2], Section 3.10).

      2.  The key for this Integrity Algorithm is computed using the
          same method as is used to compute IPsec's Integrity Algorithm
          key ([IKEV2], Section 2.17).


   When a pair of SAs are created (one in each direction), the RoHC
   channel parameter FEEDBACK_FOR is set implicitly to the other SA of
   the pair (i.e. the SA pointing in the reverse direction).

3.  Security Considerations

   The RoHC parameters negotiated via IKEv2 do not add any new
   vulnerabilities beyond those associated with the normal operation of

4.  IANA Considerations

   This document defines a new Notify Message (Status Type).  Therefore,
   IANA is requested to allocate one value from the IKEv2 Notify Message
   registry to indicate ROHC_SUPPORTED.  Note that, since this Notify
   Message is a Status Type, values ranging from 0 to 16383 must not be
   allocated for ROHC_SUPPORTED.

5.  Acknowledgments

   The authors would like to thank Mr. Sean O'Keeffe, Mr. James Kohler,
   and Ms. Linda Noone of the Department of Defense, as well as Mr. Rich
   Espy of OPnet for their contributions and support in the development
   of this document.  The authors would also like to thank Mr. Tero
   Kivinen for providing his technical expertise for this document.  In
   addition, the authors would like to thank the following for their
   numerous reviews and comments to this document:

   o  Dr. Stephen Kent
   o  Dr. Carsten Bormann
   o  Mr. Lars-Erik Jonnson
   o  Mr. Pasi Eronen
   o  Dr. Joseph Touch

   Finally, the authors would also like to thank Mr. Tom Conkle, Ms.
   Michele Casey, and Mr. Etzel Brower.

6.  Normative References

   [ROHC]     Bormann, C., Burmeister, C., Degermark, M., Fukushima, H.,
              Hannu, H., Jonsson, L., Hakenberg, R., Koren, T., Le, K.,
              Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K.,
              Wiebke, T., Yoshimura, T., and H. Zheng, "RObust Header
              Compression (ROHC): Framework and four profiles: RTP, UDP,
              ESP, and uncompressed", RFC 3095, July 2001.

   [IPSEC]    Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.


              Ertekin, E., Christou, C., and R. Jasani, "Integration of
              Robust Header Compression over IPsec Security
              Associations", work in progress , June 2006.

   [IKEV2]    Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
              RFC 4306, December 2005.

   [ROHCPPP]  Bormann, C., "Robust Header Compression (ROHC) over PPP",
              RFC 3241, April 2002.

   [AH]       Kent, S., "IP Authentication Header", RFC 4302,
              December 2005.

   [ESP]      Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005.

              Pelletier, G. and K. Sandlund, "RObust Header Compression
              Version 2 (RoHCv2): Profiles for RTP, UDP, IP, ESP and UDP
              Lite", , May 2007.


              IANA, "IKEv2 Parameters",
              November 2007. Parameters,
              January 2008.

Authors' Addresses

   Jonah Pezeshki
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


   Emre Ertekin
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


   Rohan Jasani
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


   Chris Christou
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


Full Copyright Statement

   Copyright (C) The IETF Trust (2007). (2008).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at


   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).